Is a high rT3 level an issue by itself? Or does... - Thyroid UK

Thyroid UK

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Is a high rT3 level an issue by itself? Or does it turn into a problem when rT3/FT3 ratio gets impaired?


So is elevated rT3 an issue? Or it is bad when the ratio surpasses 20?

Also I have been reading conflicting information on rT3 and rT3/FT3 ratio. At some places they say both are important factors, whereas at others it is said they don't have that big of an influence on one's wellness.

Also does everyone on T4 get a high rT3 in the end?


3 Replies

This may be helpful and look down to see an explanation of RT3. This doctor was a scientist as well and specialised in thyroid hormone resistance as well thyroid gland dysfunctions.

In my personal experience I would say a high rT3 was a problem. I felt very severely hypo when mine was high (it was way over the range).

I got mine back into the range by taking T3 only. Once I'd achieved that I experimented with NDT, back to T3, back to NDT, NDT + T3,... Whatever I do I keep coming back to T3 only. I feel at my best like that.

And of course, with T3 only I can't create rT3.

Thank you, Shaws, Humanbean!

I am already quite familiar with Dr Lowe's theories, I happen to find them very stimulating and logical.

However I am afraid of high rT3, and as Humanbean says it can turn into a problem.

Humanbean, I am the opposite of you and most people apparently.

T3 seems to make me more sick...

Whenever I add it to my T4, I get more hypo.

I guess that is due to T3 suppressing my TSH, and the suppressed TSH on its turn downregulates the FT4 (both from my thyroid and from Levothyroxine), which in turns lowers T4/T3 conversion and FT3 lowers as well. And my T3 dose is not high enough to overcome that downregulation and render my euthyroid, that is why I feel even more hypo.

Further on if I try to lower my T4 (as some suggest when adding T3 to T4), I feel even more hypo!

The other problem is I cannot tolerate more than 12.5 T3 at once. So in order to take a reasonably high total amount of T3 with which I will be able to overcome my hypo state, I have to take at least 4 doses of, let's say, 10 mcg a day.

I like Dr Lowe's stance that a high enough T3 dose should be taken at once so as to achieve cell saturation, but I was unable to achieve that.

Even with lower levels of T4 in my system, a higher than 12.5 (or 15) T3 dose still overstimulates me a little.

Since being on T3 only last year, I started straight on 125 T4 on January the first. My FT4 was very low, so I started on 125 mcg straight on, dropping the T3 from 35-37 to 25, then 15, then 12.5, then 6.

I felt great for 5-6 days and then I started becoming hypo.

Then I dropped the 6 mcg T3, went on 125 mcg T4 only and felt at my best, but again only for 5-6 days.

Added 6 mcg T3 again to 125 T4 and I have become more hypo.

Kept T3 to 6 mcg, upped my T4 to 150 mcg, felt great for a week, then again - hypo...

Droppped T3 completely. Felt great for 2-3 days only on 150 T4, then again hypo...

Although all in all on T4 only I am hundred times better than on T3 only and on T4/T3 combo...

I am really afraid of a high rT3 issue. That is the only thing stopping me from raising my 150 mcg T4 dose any further...

It seems to me there are no people who feel better on T4 only...

P.S. I know you will find it unbelievable, but T4 works instantly for me, in a matter of hours. I can judge by the number of skipped beats (my main hypo symptom) per day I have. On 150 T4 and no T3 I had no skipped beats for 4-5 days, and then they reappeared, but are still little in number, compared to the hell it was on a lower dose of T4 or T3 only. They disappeared almost completely while I was on T3 only, but my heart rate was constantly in the upper 90s - lower 100s...

With T4 ectopic beats disappear and my heart rate is in the 60-70s. However, this doesn't last long enough. I am wondering whether 200 + mcg T4 will do the trick for me, or it will become a low dose again, and I will be becoming hypo on every dose I try to raise to...

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